Deluge System

“Deluge” systems are systems in which all sprinklers connected to the water piping system are open, in that the heat sensing operating element is removed, or specifically designed as such. These systems are used for special hazards where rapid fire spread is a concern, as they provide a simultaneous application of water over the entire hazard. They are sometimes installed in personnel egress paths or building openings to slow travel of fire (e.g. openings in a fire-rated wall).

Water is not present in the piping until the system operates. Because the sprinkler orifices are open, the piping is at atmospheric pressure. To prevent the water supply pressure from forcing water into the piping, a “deluge valve” is used in the water supply connection, which is a mechanically latched valve. It is a non-resetting valve, and stays open once tripped.

Deluge Fire Sprinkler systems protect extra hazard occupancies that require significant amounts of water to cool and control the growth or development of a fire. Typically they are employed on hazards that contain low flash point flammable liquids or hazards with large amounts of combustible liquids. These types of hazards may include, oil extraction processes, transformers, tank or vessel protection, distillation processes. Water or Foam Deluge systems are used in the protection of large Aircraft Hangers as one primary means of fire protection.

Because the heat sensing elements present in the automatic sprinklers have been removed (resulting in open sprinklers), the deluge valve must be opened as signaled by a fire alarm system. The type of fire alarm initiating device is selected mainly based on the hazard (e.g. smoke detectors, heat detectors, or optical flame detectors).

The initiation device signals the fire alarm panel, which in turn signals the deluge valve to open. Activation can also be manual, depending on the system goals. Manual activation is usually via an electric or pneumatic fire alarm pull station, which signals the fire alarm panel, which in turn signals the deluge valve to open.